Edit GPS L2C Phase Correction

L2C measurements are affected by an offset relative to L2 P/Y signals. This offset is dependent not only upon the manufacturer of your GNSS receiver, but also the firmware version used. The raw GNSS converter applies a default L2C offset for each supported data type, however this may need to be adjusted for your specific receiver.

The correct L2C offset is needed in order to correctly resolve integer carrier phase ambiguities. If the incorrect L2C offset is applied, integer ambiguity resolution will fail even in ideal conditions. That is, even with a short distance between base and remote antenna, low multipath and unobstructed tracking of all available GNSS satellites, correct ambiguity resolution becomes impossible.

The RINEX converter applies a default L2C offset of 0 cycles, as it is common for receiver manufacturers to remove the L2C offset during conversion to RINEX. If this is the case, measurements will be decoded as L2C (due to a flag set within the raw GNSS data), however the correction needs to be zeroed as it has already been removed by third party software.

If converting RINEX data that is known to contain a non-zero L2C offset, or any receiver which requires a different L2C offset than is applied by default, the correct value can be entered either during conversion (see the receivers global conversion options) or after conversion using this feature. There are four possible L2C offset values regardless of receiver manufacturer or firmware version: -0.25, 0.25, 0.5 or 0.